Later this summer, following years of legal skirmishing and politicking, the Los Angeles City Council is expected to vote on whether to lift its decade-old ban on private-property murals.

Some questions surrounding the proposed ordinance have been around since at least 1932, when the Mexican muralist David Alfaro Siqueiros painted his polemical masterpiece "América Tropical" in downtown Los Angeles, which was subsequently whitewashed and finally restored last year.

Among them are: What happens when an individual artist or property owner's free-speech rights collide with another group's aesthetic preferences or personal views? Who gets to decide what's art and what's "vandalism" — elected officials, cultural appointees, police officers, neighborhood councils? And, ultimately, what sort of open-air visual environment does Los Angeles want to foster?

"We look to Paris or we look to Florence, they have their gorgeous public art, right?" says Isabel Rojas-Williams, executive director of the Mural Conservancy of Los Angeles, which supports the new measure. "Why can't we do that? Why can't we have our own Sistine Chapel on the streets?"

Yet in other, significant ways, the landscape in which the proposed ordinance is being debated is very different from that of 2003, when the city's ban went into effect — let alone from the 1930s or the early '70s, when a proliferation of murals and street art began to dramatically alter many neighborhoods.

As a result, some issues have become more complex than before, and the path toward a law that addresses those issues may be even less clear than it was in the past when the city repeatedly tried, and failed, to clarify its policies.

To begin with, muralism in Los Angeles is far from an endangered species. Despite the city's ban, and notwithstanding the whitewashing of hundreds of existing murals over the last decade, scores of other new murals and street-art projects have gone up throughout the region during the last 10 years. Some local artists who support the ordinance believe that street art will continue to flourish whether the City Council lifts the current ban.

"I have a mural lined up I'm supposed to do, across from LACMA, coming up in August," says Greg "Craola" Simkins, a South Bay artist who concocts surreal confabulations of Pop art and Old Master paintings, and whose work adorns art galleries, video games and toys as well as urban walls and Melrose Avenue alleyways. "If people in the right places say, 'You can paint this,' you can show up and nobody's going to mess with you."

The draft ordinance, whose leading sponsor has been Eastside Councilman José Huizar, would allow for the creation and preservation of original art murals and "public art installations," but not commercial advertising on private property.

A sticking point has been whether to allow new murals to be rendered on single-family (R1 zoned) structures. Another crucial provision likely to be in the final draft would protect hundreds of existing murals under a grandfather clause. The R1 provision has alarmed other elected officials, who fear that it could lead to an onslaught of new murals in neighborhoods that historically haven't wanted them.

Public attitudes toward muralism and its aesthetic kinfolk, graffiti and street art, have evolved considerably over the last several decades as these forms have been assimilated into popular culture. Mural art and graffiti, a facet of hip-hop culture, have been widely commercialized, now used in advertising and graphic design to hawk hamburgers, basketball shoes, energy drinks and Hollywood movies.

"When we all started doing it, we weren't trying to be in galleries, we weren't trying to impress the people on the hills with the money," Simkins says. "We were just painting to talk to each other, leaving marks, like, 'Oh, check out this.' It was like a sport. And now people are interested in it and want to hang it on their walls."

For some, street art has become a lucrative and name-branding practice, performed not only by amateurs and crews but also by globe-trotting artist-celebrities such as Banksy, the Brit whose works are shown in museum exhibitions and can fetch millions of dollars.

Last month a satirical mural stencil by Banksy titled "Slave Labor (Bunting Boy)," which was originally rendered on a discount shop's wall in North London and later sliced off, was purchased at auction by an unknown buyer for $1.1 million. The sale provided the latest example of the commodification of street art, and set Twitter feeds ablaze with commentary as to whether the genre is losing some of its underground cachet and socially critical, outsider stature.

"Street art and graffiti art has completely been embraced and absorbed into popular culture and disseminated globally, while at the same time still being criminalized," says Sandra de la Loza, a multimedia artist whose 2011 LACMA show, "Mural Remix," presented a visionary mash-up by sampling and recombining elements of '70s Chicano murals.

Veteran L.A. muralist John M. Valadez, who belonged to a group of pioneering Chicano art-provocateurs in the 1970s and '80s, suggested that some city policies governing public art are outdated, unsophisticated and confusing, in part because they have failed to keep pace with changing technologies, popular attitudes and the blurring of various commercial and non-commercial artistic strategies.

"To use a spray, you're like some kind of an outlaw. If I use a brush it's, 'Oh, well then, you're doing a mural,'" he said.

De La Loza sees similar contradictions toward street art. "It's ironic that despite its immense appeal and embracement by many textures of society, the last ones to accept it are the art world, and also the judicial system and city policies remain hostile to it," she said.

Indeed, major museums were among the last holdouts in granting recognition to muralism and street art. But in recent years Southern California museums have devoted entire exhibitions to them, such as the massive "Art in the Streets" show at L.A.'s Museum of Contemporary Art in 2011. That institutionalizating process has been celebrated by some, but viewed by others as the de-fanging of a previously renegade art form.

Meanwhile, new forms of graffiti- and mural-based art have continued to multiply, among them skateboard art, tattoo and body art, and sticker art. Richard and Rosanna Ahrens, owners of Sticky Rick's in Boyle Heights, are among the leading purveyors of vinyl silk-screen sticker art, a quietly booming sub-genre. Whimsical stickers, generally ranging in size from big-toe-shaped to postcard width, are increasingly being used by individuals, groups and start-up businesses not only to decorate cellphones and laptops, but also to promote products and ideas, create brand names, and to trade and circulate through social media.

Just as street art no longer is associated solely with any ethnic group, it also is no longer the exclusive intellectual property of any one social class. From East L.A. to Koreatown and the San Fernando Valley, murals have become a transglobal art form, incorporating Japanese manga art, Korean and Brazilian cartoon characters, traditional Chicano iconography and many other influences.

"A lot of the people that we work with, they have some kind of corporate job," Richard Ahrens said. "They work for Xbox, they do magazines, they do layouts, and their fun thing is stickers. Or to go along with their product or new brand."

But in spite of all these shifts, what may finally decide the ordinance's fate is a persistent belief in some quarters that murals are symptoms, if not causes, of urban decay. During the 1980s and '90s, gang members learned that one way to keep their tags temporarily safe from graffiti-abatement crews was to spray them on existing murals. That slowly led to a conflation of mural art with graffiti art.

"In L.A. we've been bombarded with a 20-year sound bite of 'graffiti equals criminal activity,'" De La Loza said. Museum exhibitions and pop culture spinoffs may widen peoples' understanding of the history of muralism and street art, and their sense of its possibilities, she believes, "but in terms of actually changing policy, I don't know," De La Loza said. "That's a whole different ballgame."